Ternary Composite System Research Articles

Investigation of the electrothermo-optical effect of a smectic LCP-nematic LC-chiral dopant ternary composite system based onSA ? N* phase transition

A sharp change in transmittance from a transparent state to a light scattering one within a tiny temperature range is induced accompanied with the heat-induced phase transition from a smectic-A (SA) phase to a chiral nematic (N*) one in a side-chain smectic-A liquid crystalline polymer (SALCP)–low-molecular-weight nematic liquid crystal (NLC)–chiral dopant ternary composite system with a homeotropic boundary condition. By adjusting the polymer ratio, an induced N* phase exhibiting strong light scattering over a wide temperature region has been obtained. The resulting scattering texture retained in the SA phase due to fast cooling from the N* phase can be rather stable and can be easily erased by cooling slowly from the N* phase to the SA phase after the scattering texture being heated into the N* phase again or by application of an alternating current electric field on the scattering texture directly. Based on these characteristics, it is very possible that this composite system will be used as a novel thermal addressed liquid crystal display material with respect to a fast response, a high contrast, and a durable memory effect. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 623–631, 1999

Laser-addressing rewritable optical information storage of (liquid crystalline side chain copolymer/liquid crystals/photo-responsive molecule) ternary composite systems

A laser-addressing rewritable optical information storage for (liquid crystalline side chain copolymer: LCcoP/low molecular weight nematic liquid crystals: nematic LCs/photo-responsive molecule: PM) ternary composite systems in a smectic state was investigated on the basis of a reversible and bistable electro-optical switching driven by ac electric fields with two different frequencies. In order to improve the response speed for the electro-optical switching for the ternary composite system, a LCcoP with the mesogenic side chain fraction of 52.5mol% was synthesized. The ternary composite system with the LCcoP fraction of 36wt% showed a smectic state over a wide range near room temperature. High speed reversible and bistable electro-optical switching (∼100ms) under an appropriate electric field, and a stable memory effect (∼y) were demonstrated upon irradiation of UV light of 355nm by using a YAG laser for the ternary composite systems in a smectic phase at room temperature.

萌芽的研究発表論文 ＭＧおよびＭＡ法による熱電変換材料の高性能化

We have examined the thermoelectric properties of Co1-xFexSb3 ternary system and CoSb3-FeSb2 composite system. The Seebeck coefficient and the electrical resistivity are generallyreduced by the substitution for Co by Fe. The thermal conductivity is also reduced by the substitution especially at high iron content region. These behaviors of the thermoelectric properties in the samples with low iron content are ascribed to the substituted Fe, while those in the samples with high iron content are ascribed to the precipitated FeSb2 (Fe0.73Co0.27Sb2) compound. Co0.75 Fe0.25Sb3 has a maximum value of figure of merit of 4.8×10-4 K-1 at 773K. For the purpose of more reducing of the thermal conductivity, we have prepared the CoSb3-FeSb2 composite where the FeSb2 particles are dispersed in the CoSb3 matrix by MG (mechanical grinding) technique. The thermal conductivity of the composite is smaller than that of Co1-xFexSb3. The electrical resistivity of the composite increases with increasing MG time, but it is smaller than that of CoSb3 at high temperature. The decrease of the thermal conductivity and the less increase of the electrical resistivity are ascribed to the enhancement of the phonon scattering caused by the dispersed FeSb2 in the matrix and the low electrical resistivity of FeSb2, respectively. As a result, the composite whose molar ratio of CoSb3 to FeSb2 is 0.7 to 0.3 and MG time is 25h has a maximum value of figure of merit of 6.1×10-4 K-1 at 756K. This value is larger than the maximum value of 4.8×10-4 K-1 for Co1-xFexSb3 system.

Effects of Composition on Thermo-Optical Properties of (Side Chain Smectic-A Liquid Crystalline Polymer/Low Molecular Weight Nematic Liquid Crystal/Chiral Dopant) Ternary Composite System

A drastic change from a transparent smectic-A (SmA) phase to a light-scattering chiral nematic (N*) one is achieved in [side chain smectic-A liquid crystalline polymer (SCSmALCP)/low molecular weight nematic liquid crystal (LMWNLC/chiral dopant] a ternary composite system with a homeotropic boundary condition. The light-scattering state of the induced N* phase can be resumed into the initially transparent SmA phase on cooling slowly, and be frozen in the SmA phase on cooling rapidly. The effects of the composition of the ternary composite system on such thermo-optical characteristics are investigated.

The thermally sensitive characteristics of a (smectic LCP/ nematic LC/chiral dopant) ternary composite system

A transition between the transparent smectic A (SmA) phase and the light scattering chiral nematic (N*) phase was realized based on the thermally induced SmA N* phase transition for the homeotropically aligned \\[liquid crystalline polymer (LCP)/liquid crystal (LC)/chiral dopant] ternary composite system. The LCP played an important role in increasing the intensity of the light scattering of the heat-induced N* phase. Meanwhile the effects of the composition of the ternary composite system on the thermo-optical characteristics were also investigated.

Improvement in Response Speed for Bistable Light Switching of (Liquid Crystalline Polymer/Low Molecular Weight Liquid Crystals) Ternary Composite System in Induced Smectic State

Bistable light switching characteristics of the composite system composed of side chain type liquid crystalline polymer (LCP) and two kinds of low molecular weight liquid crystals (LCs) have been investigated. Each component was in a nematic state but the ternary composite showed an induced smectic phase over the wide ranges of both mixing concentration and temperature. The reversible turbid (light scattering)-transparent switching was observed upon the application of electric fields with low and high frequencies, respectively. Both transparent and turbid states of the ternary composite could be maintained stably, even though an electric field was turned off. The ternary composite system exhibited novel characteristics on bistable and reversible light switching. The response speed for bistable light switching could be remarkably improved by reducing the LCP fraction, maintaining an induced smectic state. Then, a novel type of the (LCP/LCs) composite system with a short response time at room temperature was realized for that with bistable and reversible light switching.

Rewritable Optical Storage Effect of (Liquid Crystalline Polymer)/(Low Molecular Weight Liquid Crystal)/(Photoresponsive Molecule) Ternary Composite System

Abstract A rewritable optical storage effect induced by photoirradiation to a (liquid crystalline polymer)/(low molecular weight liquid crystal)/(photoresponsive molecule) ternary composite system was investigated. Turbid and transparent states were reversibly switched upon photoirradiation with ultraviolet and visible light, respectively, under the application of an a. c. electric field. A light-addressed optical storage of the composite film was demonstrated.